Method for grinding bevel- or hyperboloid-shaped gears

ABSTRACT

A method of, and apparatus for, grinding bevel- or hyperboloidshaped gears having lengthwise curved teeth with the aid of a grinding body rotating about its axis, wherein the axis of the grinding body is moved within a tooth gap and continuously along an endless path. The apparatus for the performance of the aforesaid method contemplates the provision of a number of grinding bodies which are rotatably mounted about their axis at a circle at a grinding wheel or head, and wherein the grinding wheel is rotatable about an axis containing the center of the aforesaid circle. Drive means serve for the rotation of the grinding bodies.

United States Patent 1191 Kotthaus METHOD FOR GRINDING BEVEL- OR HYPERBOLOID-SHAPED GEARS [75} Inventor: Erich Kotthaus, Kloten, Switzerland (73] Assignee: Werkzeugmaschinenfabrik Oerlikon Buhrle, Zurich. Switzerland 221 Filed: Oct. 16,1972

21 Appl.No.:297,986

[ June 24, 1975 Bock 5 [/90 Cantrell 90/5 [57] ABSTRACT A method of, and apparatus for, grinding bevelor hyperboloid-shaped gears having lengthwise curved teeth with the aid ofa grinding body rotating about its axis, wherein the axis of the grinding body is moved within a tooth gap and continuously along an endless path. The apparatus for the performance of the aforesaid method contemplates the provision of a number of grinding bodies which are rotatably mounted about their axis at a circle at a grinding wheel or head, and wherein the grinding wheel is rotatable about an axis containing the center of the aforesaid circle. Drive means serve for the rotation of the grinding bodies.

2 Claims, 3 Drawing Figures JUN24|975 3.891.407 PATENTED SHEET 1 FIG. 1

PATENTED JUN 24 m5 SHEET 1 METHOD FOR GRINDING BEVEL- OR HYPERBOLOID-SHAPED GEARS BACKGROUND OF THE INVENTION The present invention relates to a new and improved method of grinding bevelor hyperboloidshaped gears with lengthwise curved teeth with the aid of a grinding body rotating about its axis and also pertains to a new improved construction of apparatus for the performance of the aforesaid method.

According to a known prior art technique of this type bevelor hyperboloidshaped gears are ground in that there is employed a single grinding disk, wherein during an indexing type method technique one tooth gap after the other must be ground.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a new and improved method by means of which it is possible to continuously grind all of the tooth spaces or gaps and also the provision of a new and improved apparatus for the performance of the aforesaid method.

The method aspects of this development are characterized by the features that the axis of the grinding body moves within a tooth gap and continuously along an endless path.

The alpaaratus for the performance of the aforesaid method is manifested by the features that a number of grinding bodies are mounted to be rotatable about their axis at a circle at the grinding wheel, that the grinding wheel is rotatable about an axis containing the center of the aforesaid circle and is provided with a drive for rotating the grinding bodies.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1 is a longitudinal sectional view through a grinding wheel or head of the inventive apparatus;

FIG. 2 is a top view of the grinding wheel of FIG. I; and

FIG. 3 illustrates a machine employing the grinding wheel illustrated in FIGS. 1 and 2 for grinding bevelor hyperboloid gears.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, it will be understood that a grinding wheel or head possesses eleven grinding bodies 11 arranged along an outer circle having a radius Ka and eleven grinding bodies 12 arranged along an inner circle having the radius K,-. As best seen by referring to FIG. 2 different angular spacings prevail between these grinding bodies 11 and 12, and specifically there are provided a smaller angular spacing d), and a larger angular spacing (1) so that there are formed groups of two respective grinding bodies 11 and 12 which respectively engage in a tooth gap or space of the gear to be ground. The grinding bodies 11 can be employed for grinding the convex tooth flanks and the grinding bodies 12 for grinding the concave tooth flanks. Further, the axis of each of the grinding bodies is rolled along a curve corresponding to the directrix of the associated gear tooth.

According to the showing of FIG. 1 the grinding wheel or head 10 possesses a base body 13 having a conical bore 14 by means of which this grinding wheel 10 can be secured to a non-illustrated work spindle. To this base body 13 there is attached a retaining or holder ring 15 with screws 16. The eleven inner grinding bodies 12 are secured to this retaining ring 15. Further, there are directly secured to the base body 13 the outer grinding bodies 11. As will be more fully explained, both the inner and outer grinding bodies 11 and 12 are radially displaceable. For this purpose there is provided for each inner grinding body 12 a holder or support 17 which is radially displaceably supported at the retaining ring 15. With the aid of an adjustment screw 18 the holder 17 can be displaced in radial direction, and with the aid ofa fixing screw 19 it can be fixed in desired position. In order to ensure that the holder 17 does not undesirably shift when the fixing screw 19 is released there is provided a blade spring 20. Further, tow blade springs 21 are secured at each holder 17, between which there is mounted an inner grinding body 12. In analogous fashion the outer grinding bodies 11 are displaceable at holders or supports 22 at the base body 13. The holder 22 is displaceable in radial direction with the aid of an adjustment screw 23 and can be fixed in desired position with the aid of a fixing screw 24. Here also a blade spring 25 secures the holder 22 against any unintentional displacement when the fixing screw 24 is released. At each holder 22 there are secured two blade springs 26, between which there is rotatably mounted an outer grinding body 11.

To adjust the angular spacing d), and 42 the retaining ring 15 is rotatably secured to base body 13. To rotate the retaining ring 15 upon the base body 13 it is sufficient to release the screws 16.

The grinding bodies 11 and 12 are composed of a conical tip 11a and 12a and a cylindrical portion 11b and 12b respectively. Such outer grinding bodies 11 are seated upon a spindle 27, the rear end face 28 of which is arched or domed. This end face 28 bears upon a first ring-shaped control disk 29. This first control disk or cam 29 is secured at housing 30, in which is mounted the non-illustrated work spindle, and does not rotate together with the grinding wheel or head 10. In analogous manner the inner grinding bodies 12 also bear upon a second ring-shaped control disk or cam 31. The second control disk 31 is secured in any suitable and therefore not particularly illustrated fashion at the first control disk 29. With the aid of such control disks 29, 31 the inner and outer grinding bodies 11, 12 can be displaced in axial direction while bending through the blade springs 21 and 26 respectively. Both control disks 29 and 31 are suitably adjustably secured to the housing 30.

Both the inner and the outer grinding bodies 11 and 12 are rotatable about their own axis and are driven pneumatically. For this purpose each grinding body 11, 12 is provided with a penumatic drive motor 32, which has not been particularly illustrated in the drawing since it can be of conventional design. A compressed air conduit or line 33 leads to each drive motor 32, the compressed air conduit 33 being attached to the base body 13. A channel 34 is provided at the base body 13 for each compressed air conduit 33. All of the channels 34 open into a ring-shaped compartment 35 at the interior of a stationary grinding ring 36. The ring-shaped compartment 35 is connected through the agency of a hose 37, secured to the grinding ring 36, with a nonillustrated compressed air source.

The grinding wheel or head described in conjunction with FIGS. 1 and 2 is employed in a machine known as such in the art and generally illustrated in FIG. 3. This machine embodies a V-belt 7AM driven by a non-illustrated motor. This motor drives the grinding wheel or head 10 through the agency of a the aforementioned V-belt as well as through the agency of a transmission A. Transmission A renders possible switching to four different speeds. Further, this transmission A possesses four change gears A1, A2, A3, A4, so that grinding wheel can be driven at eight different rotational speeds. At the gears designated by reference character B there is provided an intermediate gear 6A2, by means of which the direction of rotation of the grinding wheel can be reversed. This renders possible the grinding of hyperboloid gears. The shaft 3A1, at which there is secured the grinding wheel 10, can be inclined with regard to the shaft 4A2. For each inclination the gears designated by reference character C must be exchanged. Owing to this inclination there also can be ground a very flat gear without the grinding bodies contacting the gear at its path when they move in front of and past the teeth of the gear to be ground. At the shaft 1T2 there is secured the gear to be ground. This shaft 1T2 is driven by a differential gearing or differential tranmission D through the agency of different change gears T1, T2, T3, T4 as well as via the shafts 7T1, 7T2, 7T3 and 2T1. A roller drum 40, at which is located the grinding wheel 10, is driven by an endless worm 6W 1. This worm 6W1 is connected with a trans mission box S rendering possible changeover to eighteen different speeds. The movement of the roller drum is transmitted with the desired transmission ratio to a satellite support of the differential transmission D. Between the transmission box S and the differential transmission D there are arranged change gears W1 to W6. An auxiliary motor E is provided for the purpose of rapidly moving the roller drum back into its starting position.

The mode of operation of the described apparatus is as follows: at the machine depicted in FIG. 3 there are produced the gears which are to be ground with the aid of the inventive apparatus. For this purpose there is mounted at this machine instead of the grinding wheel 10 a cutter head or tooth cutter which has not been illustrated in the drawing. The cutting operation occurs in a manner well known to those skilled in the art and therefore is not here further explained, especially since details of the cutting operation do not constitute subject matter of this invention. The gear produced in the conventional manner upon the machine depicted in FIG. 3 now can be ground in that there is mounted at the machine. instead of the cutter head, the grinding wheel or head 10. For grinding the gear the machine is placed into operation in the same manner as during cutting of the gear.

For crown or chamber grinding of the gears there are employed the control disks 29 and 31 which render possible axial displacement of the grinding bodies 11 and 12. Owing to this axial displacement of the grinding bodies 11 and 12 the gear can be ground in crowned or cambered manner in the desired way. In order to be able to change the load bearing surface of the tooth flank it is necessary to alter the position of the control disks. This can occur either solely by adjusting the control disks 29, 31 at the housing 30 or by exchanging such control disks 29, 31 for control disks of a different shape or configuration.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,

What is claimed is:

l. A method for grinding bevelor hyperboloidshaped gears with lengthwise curved teeth with the aid of a grinding head at which there are arranged a number of grinding bodies, said method comprising:

1. Simultaneously carrying out the following steps:

a. rotating the gear to be ground about its own axis;

b. rotating the grinding bodies about their own axes;

c. rotating the grinding head about its own axis; and

d. rotating the axis of the grinding head about a stationary axis.

2. The method as defined in claim 1, further including the step of displacing the grinding bodies in axial direction with respect to the grinding head for cambergrinding the gear. 

1. A method for grinding bevel- or hyperboloid- shaped gears with lengthwise curved teeth with the aid of a grinding head at which there are arranged a number of grinding bodies, said method comprising:
 1. SImultaneously carrying out the following steps: a. rotating the gear to be ground about its own axis; b. rotating the grinding bodies about their own axes; c. rotating the grinding head about its own axis; and d. rotating the axis of the grinding head about a stationary axis.
 2. The method as defined in claim 1, further including the step of displacing the grinding bodies in axial direction with respect to the grinding head for camber- grinding the gear. 